Table 1.

Classification of vegetables according to inorganic nitrate content (mg/100 gm fresh weight)

Class I (< 20)	Artichoke, asparagus, broad bean, Brussels sprouts, eggplant, garlic, onion, green bean, mushroom, pea, pepper, potato, squash, tomato
Class II (20 to < 50)	Broccoli, carrot, cauliflower, cucumber, pumpkin, chicory
Class III (50 to < 100)	Cabbage, dill, turnip, Savoy cabbage
Class IV (100 to < 250)	Celeriac, Chinese cabbage, endive, escarole, fennel, kohlrabi, leaf chicory, leek, parsley
Class V (> 250)	Celery, chervil, cress, Lamb's lettuce, lettuce, radish, red beetroot, rocket (rucola), spinach, Swiss chard

data from references^6–9.